This invention relates generally to telecommunications receiving equipment and is particularly directed to apparatus for directing incoming calls on a single telephone line to a telephone or one of a plurality of communications devices in accordance with coded pulses in the ring signal.
Coded ring signals are used in telephone communications to indicate which of several telephones on a single line the caller wishes to reach. Ring-Master is a service currently available that provides different ring signals to a single telephone line for switching to up to three different telephone numbers on a single line. An example of this is where three members of the same family may have different telephone numbers, but will be charged for only a single telephone line plus the Ring-Master service charge. When any one of the three telephones numbers is dialed, the telephone company switches the call to the single telephone line and provides a different sounding ring signal for that particular desired telephone number. In this system all of the telephones on the line ring at the same time with the same ring.
So long as the human element in terms of answering the telephone is present, this ring coded approach is acceptable. Even a single machine that uses a telephone network such as a computer modem, a facsimile, a telex, etc., which is set to answer on a fourth or higher ring may be coupled to the single telephone line and become part of the Ring-Master system. However, the coded pulse approach cannot accommodate two or more such machines which are capable of only counting the number of rings and cannot recognize and operate on a given ring signal pattern.
The present invention addresses the aforementioned limitations of the prior art by providing an apparatus and method for monitoring incoming ring signals, detecting the ring signal pattern, and automatically switching the call to a telephone or to one of a plurality of machines coupled to a single telephone line in accordance with the particular ring signal received. The ring signal is provided with a pulse pattern for designating the telephone or particular machine which has been dialed. The present invention also senses when one of the telephones or machines goes Off-Hook in trying to place a call and connects that telephone or machine to the single telephone line to provide a Dial Tone. In this way, two or three machines can share a single telephone line without interfering with each other or with outgoing telephone calls on the same line. The incoming ring signal is provided with coded information which the present invention detects, interprets and then decides to which telephone or device the incoming call is to be routed.